What would the seasons be like if the axis of earth's rotation was tilted 0 degrees to the ecliptic, instead of the 23.5 degrees we find it today? what about if it was tilted 0 degrees?

The seasons would become constant. It would be equinox throughout the year.

Step-by-step explanation:

The earth would be in a state of constant equinox i.e., the length of day and night would be same in a particular place.

The season of a place would be what it is when it is normally titled at equinox.

The animal and plant life which depend on the seasons would be affected.

Snow would only occur at parts where it normally snows at equinoxes.